Bush widening apparatus and process for forging a bush blank

ABSTRACT

The invention relates to a bush widening apparatus and a process by means of which it is possible to partially, in sections, forge at relatively low investment costs large and heavy bush blanks by means of a motor-driven, e. g. hydraulic, forming tool, and during which process both the diameter and the height of these banks increase in size.

BACKGROUND OF THE INVENTION

The invention relates to a bush widening apparatus.

Furthermore, the invention relates to a process for forging a bush blank.

Large bushes with individual piece weights of up to 400 tons, diameters of up to 8,000 millimeters and heights of three to nine meters are normally forged over a mandrel. But often the quality is not sufficient.

Also known in the art is the use of large ring rolling mills. The related investment costs are very high. With relatively low piece numbers, the investment costs for such ring rolling mills often do not match the results.

DISCLOSURE OF THE INVENTION

The object of the present invention is to propose a bush widening apparatus with substantially lower investment costs in comparison to the state of the art while still ensuring good product quality.

Another object of the invention is to provide a suitable forging method.

The object of the invention is achieved with a bush widening device wherein a large perforated bush blank having a weight of many hundreds of tons, e. g. approximately 200 to 600 tons, having a diameter of 3,000 to 10,000 millimeters, having a height of one to nine meters, can be drawn over a forging mandrel which has extending through it a channel, and wherein the channel has a suitable cooling agent, preferably cooling water, flowing through it, which can be fed continually into the channel from above or below and that is drained, for example, below to a collection reservoir or drain, and wherein the cooling agent supply is, for example, incorporated as part of the entire facility, and wherein the forged bush blank can be further processed, for example, into rings, lengths of pipe or pipes, and wherein the bush blank can be placed upon support rollers and partially forged at small angles at circumference by at least one laterally disposed, intermittently motor-driven forming tool, and wherein, after each forging stroke, the bush blank can be radially moved away from the forging mandrel and rotated by a small angle around the longitudinal axis of the forging mandrel in a cycle-wise fashion while being supported on the forging mandrel and after which time it can be worked again by the respective forming tool, and wherein the support rollers can be in part motor-driven in a time cycle-wise manner, and wherein the forging mandrel can be locked in its operating position by a counter-support which absorbs the forging forces entirely or in part, and wherein at least one laser device is disposed that permanently measure the outer diameter of the bush blank and move the work piece via centering and support rollers in the correct operating position relative to the forging mandrel and the respective forming tool, and wherein the forging process occurs very rapidly by forging strokes of between 30 to 60 strokes per minute, until the respective laser device gives the signal “diameter achieved” and the forging process is brought to a halt, and wherein in order to achieve the exactly desired bush shape laser measurements are taken at different locations and any necessary corrections can be made by skipping several forging steps.

The bush-widening apparatus according to the invention provides for the possibility of, for example, reshaping conically ingot molds to cylindrical bushes. In this context it is possible to process and/or forge individual piece weights weighing many hundreds of tons, e.g. 200 to 600 tons, preferably approximately 400 tons, and diameters of 3,000 to 10,000 millimeters, preferably approximately 8,000 millimeters, and total heights of one to nine meters, preferably three to six meters, by section-wise reshaping on the outer side. These bush blanks are forged intermittently by a forming tool; i.e., they are forged in cycles. Using an electric hoist crane, the bush blank is, for example, placed over the forging mandrel and on support rollers. After closing the counter-support, the partial, which means cycle-wise, forging process starts. After each stroke the centering rollers move the bush blank somewhat away from the forging mandrel rotating it by a small angular measure around its longitudinal axis, before the next forging stroke is executed. The mandrel is rotated by the same angle. Laser measuring systems can move the centering rollers into the correct operating position. The cycle-wise changes during forging, and thereby the partial forging, can be very fast, e.g. between 30 and 90 strokes, preferably between 40 and 60 strokes per minute. In addition, conical blanks can be expanded to cylindrical bushes, thereby also expanding the height of the bush.

In one embodied example, several forming tools are disposed along the circumference of the bush blank that partially work the bush blank, synchronously cycle-wise or alternating cycle-wise, at its outer jacket area.

The forming tools can be configured as spherical, convex or textured on the side that is directed toward the bush blank.

If the bush becomes conical at the beginning or during forging, the saddle, meaning the forming tool, skips some strokes at the end of the largest diameter of the bush blank. In the alternative, using a continuous saddle/forming tool it is possible to slant the latter by different positioning or by using a textured saddle/forming tool.

It is also especially advantageous to envision at least one compressed-water scale removal device that removes scale from the inside and/or outside of the bush by high-pressure water jets.

It is possible to incorporate the actuating devices for the centering rollers, as well as the support rollers, but also for the compressed-water scale removal and the motor-driven actuators of the one or several forming tools in the context of a subsequent control system. It is also possible to control or adjust the compressed water supply by section and/or by volume and/or by temperature.

In one embodiment of the bush widening device, the respective forming tool is configured in such a way as to allow for achieving maximum lengthening of the bush blank, while another solution provides that the respective forming tool is actuated by two or several drive devices, for example hydraulically.

According to the process of the present invention, for forming a bush blank said bush blank is supported by its opening on a forging mandrel and comprised of a steel alloy or similar flame-heated material having an opening extending through it and being partially forged by one or several forming tools, which are disposed over its circumference and/or height, in angular sections by rotating the bush blank, and wherein the bush blank is supported on the forging mandrel during the forging process. This bush blank is made of steel and usually weighs many hundreds of tons, e. g. approximately 200 to 600 tons, preferably 400 tons, has a diameter of 3,000 to 10,000 mm, preferably 8,000 mm, has a height of one to nine meters, preferably three to six meters, and wherein the forging mandrel is usually cooled by cooling water or another cooling agent that runs through a channel extending inside the mandrel.

In the process according to another aspect of the invention, the forging mandrel is rotated by the same size angle as the bush blank. On the one hand, this results in good cooling action and, on the other hand, good absorption of the reaction forces during the forging process.

It is especially advantageous if the bush blank is forged over its circumference and/or height by several forming tools, simultaneously or intermittently.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages can be derived from the following description of the drawings that illustrate the invention—in part schematically—in further detail in an exemplary manner. Shown are in:

FIG. 1 a bush widening apparatus according to the invention in operating position;

FIG. 2 a schematic top view of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

The reference symbol 1 denotes a machine frame that is suitably comprised of steel and that can be supported on silent blocks or on vibration-dampening cement. The machine frame 1 can be part of an encapsulated housing (not depicted here in detail) and inside which the entire bush-widening apparatus is disposed, thereby protected against splash water and sealed against contamination.

The reference symbol 2 denotes three press cylinders that are comprised herein of one differential piston respectively; and they can be applied with, in turn on both sides, with pressure by a pressure means, in particular hydraulically, supplied by one or several hydraulic sources(s) which are not shown here, by a system control or adjustment. The reference symbol 3 refers to saddle fastener(s) that is (are) powered by the respective press cylinder 2. The embodied example that is represented in FIG. 1 shows the three press cylinders driving a common forming tool 4 that extends over the entire height H and/or somewhat above of the bush blank 5. The individual press cylinders 2 can also power separate forming tools, either synchronously or separately. Furthermore, it is possible to dispose several forming tools over the height and/or the circumference of the bush blank, and thereby also over the circumference of the forging mandrel 7, that are powered jointly or by separate press cylinders 2. In addition, it is possible to trigger the press cylinders separately in order to change, if necessary, the forming tool 4 or forming tools (not shown) in terms of the height and/or angle relative to the bush blank 5 and to thereby forge the bush blank 5. Presently, the bush blank is configured as a cast ingot mold of substantially cylindrical construction form having a weight of e. g. 400 tons. The height H can be e. g. three to nine meters, while the diameter D in the shown embodied example is up to 8,000 mm. Approximately in the center, the bush blank 5 has a perforation 6 or opening through which the forging mandrel 7 reaches, which is replaceably disposed in a bearing 8. The bearing 8 is also disposed in the context of the machine frame 1, if necessary with a vibration-dampening characteristic.

In the shown embodied example, the forging mandrel 7 has a coaxially placed channel 9 that is supplied with cooling agent from a suitable cooling agent source, preferably cooling water, which is continually fed thereto from above or below and drained below, for example, into a collection reservoir or drain line (not shown here). The cooling agent supply can be incorporated in the control system of the overall installation. This type of cooling can also be used e. g. for the saddle, the centering rollers and the support rollers.

The reference symbol 10 denotes the counter-support that is movable around a pivot axis 11 in the direction A and/or B and can therefore be moved away from the forging mandrel 7.

The reference symbol 12 denotes a motor-driven rotary actuator for the forging mandrel 7 having the ability to intermittently or continually rotate or stop around its longitudinal axis in one or in both directions.

The counter-support 10 locks the forging mandrel 7 in place over a receptacle 13, which, as shown in the shown embodied example, surrounds the forging mandrel 7, which is conical at its upper end, with radial play or a positive closure around a certain part of its axial length thereby locking it in place and/or radially guiding it. If necessary, it is possible to use radial bearings herein in order to facilitate the rotary movement of the forging mandrel 7 around its longitudinal axis. Moreover, if necessary, the bearing 8 can have suitable bearings, preferably roller bearings, allocated to it that also facilitate the rotary movement of the forging mandrel 7.

The bush blank 5 rests on motor-driven support rollers 14 the actuating devices of which can also be incorporated in the overall manufacturing control system.

Laser devices are disposed at reference symbols 15 and 16 representing a laser system that radially controls, for example, centering and support rollers 17, 18, which are distributed over the circumference of the bush 5, bringing them in the correct operating positions via motor-driven or hydraulic drives 19, 20, 21 and/or 22 and locking them in the respective movement position as well.

Reference symbol 23 depicts a scale removal device that uses jets to spray pressurized water onto the surface of the bush blank thereby removing scale (inside and/or outside). It is also possible to dispose several spray jets or spay jet bars of this type of a scale-removal device 23 over the circumference. The water can be supplied to the jets corresponding to the temperature and/or the volume of the bush blank by a temperature control and/or volume control and/or temperature adjustment and or volume adjustment. The scale drops below and is removed though an opening (not shown) and a conveyor that is disposed below the device.

The hydraulic and the electrical control mechanisms of the overall installation are not shown in detail.

The type of action of the bush widening device is as follows:

While the counter-support 10 is moved up and the machine room is open, an electrical hoist crane places the bush blank 5 over the forging mandrel 7 onto the support rollers 14. After the holding-in-place device 10 has been closed, the sectional forging process begins by a corresponding application of hydraulic pressure to the respective press cylinder 2, which causes the respective forming tool 4 to act intermittently upon the outside jacket area of the bush blank 5. After each stroke of the press cylinder 2 the centering rollers 17 and 18 move the bush blank 5 further from the forging mandrel 7 and rotate the bush blank 5 by a cycle along the direction of the circumference. Before the next forging stroke is executed, the laser measuring system places the centering rollers 17, 18 and any that follow in the correct operating positions. This cycle-wise switch during forging occurs very quickly; e. g., with 60 forging strokes per minute, until the laser device gives the signal “diameter achieved” and the forging process is shut down. Laser measurements are taken at various locations in order to achieve the exactly sought-after bush shape. Any needed corrections are then made by skipping some saddles.

If the bush blank 5 becomes conical at the beginning or during the forging process, the respective forming tool 4 skips several strokes at the end of the larger diameter. In the alternative, if a continuous forming tool is employed, using different positions of the press cylinder 2 and/or the forming tool 4, it is possible to place the tool in a slanted position; or it is possible to use a textured forming tool 4. This way, it is possible to forge conically cast ingot molds into cylindrical bushes or pipes of high weights ranging, for example, to 400 tons and with diameters of, for example, 8,000 millimeters and heights from three to nine meters over the forging mandrel 7. Due to the high cycle number during the rotation of the forging mandrel 7, on the one hand, and the bush blank 5, on the other hand, it is possible to achieve a high degree of surface accuracy, as well as preset wall thicknesses of the bush blank 5 and the finished bush 5 that are within the tolerances. Subsequent to or during the process it is possible to remove scale with pressurized water from the outside and, if necessary, from the inside of the bush blank 5 by way of the descaling device 23.

The characteristics that are described in the summary, the patent claims and the description as well as illustrated in the drawings can be essential for the implementation of the invention either individually or in combination.

REFERENCE SYMBOLS

-   1 Machine frame -   2 Press cylinder -   3 Saddle fastener -   4 Forming tool -   5 Bush blank, bush -   6 Perforation, opening -   7 Forging mandrel -   8 Bearing -   9 Channel -   10 Counter-support -   11 Pivot axis -   12 Drive, motor-driven, rotary actuator -   13 Receptacle -   14 Support roller -   15 Laser device -   16 “ ” -   17 Centering and support rollers -   18 “ ” -   19 Drive, motor-driven -   20 “” -   21 “” -   22 “” -   23 Descaling device -   A Pivot direction, holder -   B ” -   D Diameter -   H Height of a bush blank 

1-30. (canceled)
 31. Bush widening device wherein a large perforated bush blank having a weight of many hundreds of tons, e. g. approximately 200 to 600 tons, having a diameter of 3,000 to 10,000 millimeters, having a height of one to nine meters can be drawn over a forging mandrel which has extending through it a channel, and wherein the channel has a suitable cooling agent, preferably cooling water, flowing through it, which can be fed continually into the channel from above or below and that is drained, for example, below to a collection reservoir or drain, and wherein the cooling agent supply is, for example, incorporated as part of the entire facility, and wherein the forged bush blank can be further processed, for example, into rings, lengths of pipe or pipes, and wherein the bush blank can be placed upon support rollers and partially forged at small angles at circumference by at least one laterally disposed, intermittently motor-driven forming tool, and wherein, after each forging stroke, the bush blank can be radially moved away from the forging mandrel and rotated by a small angle around the longitudinal axis of the forging mandrel in a cycle-wise fashion while being supported on the forging mandrel and after which time it can be worked again by the respective forming tool, and wherein the support rollers can be in part motor-driven in a time cycle-wise manner, and wherein the forging mandrel can be locked in its operating position by a counter-support which absorbs the forging forces entirely or in part, and wherein at least one laser device is disposed that permanently measure the outer diameter of the bush blank and move the work piece via centering and support rollers in the correct operating position relative to the forging mandrel and the respective forming tool, and wherein the forging process occurs very rapidly by forging strokes of between 30 to 60 strokes per minute, until the respective laser device gives the signal “diameter achieved” and the forging process is brought to a halt, and wherein in order to achieve the exactly desired bush shape laser measurements are taken at different locations and any necessary corrections can be made by skipping several forging steps.
 32. Bush widening apparatus as claimed in claim 31, characterized in that several forming tools are disposed around the circumference of the bush blank that partially forge the bush blank, synchronously in a cycle-wise manner or alternating in a cycle-wise manner, at its outer jacket area.
 33. Bush widening apparatus as claimed in claim 32, characterized in that the forming tools are configured as spherical, convex or textured on their side that is directed toward the bush blank.
 34. Bush widening apparatus as claimed in claim 31, characterized in that one or several forming tools can be brought to a standstill in order to skip several forging strokes during the forging process or in that by utilizing different positions of the forming tool or a corresponding texturing of the forming tool it is possible to compensate for diameter variations on the bush blank.
 35. Bush widening apparatus as claimed in claim 31, characterized in that a descaling device is envisioned that removes scale from the outer circumference and/or the inside of the bush blank, and wherein the descaling device comprises one or several high-pressure nozzles that direct their jets against the outer side and/or the inner side of the bush blank, and characterized in that the compressed water supply can be controlled or adjusted correspondingly by the temperature and/or the volume of the bush blank.
 36. Bush widening apparatus as claimed in claim 31, characterized in that the motor-driven actuation devices of the centering rollers as well as the motor-driven actuation devices for the support rollers, but also the descaling device and the motor-driven actuation devices of the one or multiple forming tools are incorporated in a subsequent control system and wherein the drive devices are CNC-controlled.
 37. Bush widening apparatus as claimed in claim 31, characterized in that the respective forming tool is configured in such a way that a maximum lengthening of the bush blank can be achieved.
 38. Bush widening apparatus as claimed in claim 37, characterized in that the respective forming tool is driven by two or more actuating devices.
 39. Bush widening apparatus as claimed in claim 31, characterized in that the bush blank is made of steel.
 40. Bush widening apparatus as claimed in claim 31, characterized in that the bush blank has a height of three to six meters.
 41. Bush widening apparatus as claimed in claim 31, characterized in that the forging process occurs by forging strokes between 40 to 60 strokes per minute.
 42. Process for forming a heat-forged, perforated bush bank comprised of a steel alloy or a similar material weighing many hundreds of tons having a diameter of 3,000 to 10,000 mm a height of one to nine meters, having a channel extending through it for the purpose of the forging mandrel onto which the bush blank is drawn, and wherein the bush blank is partially forged in angular sections at its circumference area by one or several forming tools, which are disposed in an offset manner over its circumference and/or height, by rotation of the bush blank and/or the forging mandrel and/or the counter-support, and wherein during the forging process the bush blank is supported on the forging mandrel, and wherein the forging occurs very rapidly at forging strokes of 30 to 60 strokes per minute, and wherein at least one laser device are envisioned that permanently measure the outside diameter of the bush blank and that move the work piece in the correct operating position relative to the forging mandrel via centering and support rollers, and wherein the forging process is brought to a halt when the respective laser device gives the signal “diameter achieved,” after which time the forging process is discontinued.
 43. Process as claimed in claim 42, characterized in that the forging mandrel is rotated by the same amount as the bush blank.
 44. Process as claimed in claim 42, characterized in that the bush blank is being forged, simultaneously or intermittently, by one or several forming tools that are disposed over its circumference and/or its height.
 45. Process as claimed in claim 42, characterized in that the bush blank has a height of three to six meters.
 46. Process as claimed in claim 42, characterized in that the forging occurs at forging strokes at 40 to 60 strokes per minute. 